Embodiments relate generally to the field of fluid delivery systems. More specifically, the embodiments relate to an apparatus and method for removing air bubbles or another gas from a fluid delivery system.
An air embolism can occur when an air bubble or embolus becomes trapped in a blood vessel or in the heart and obstructs the normal flow of blood through the blood vessel (e.g., a vascular air embolus (VAE)) or the heart. Air in a patient's veins can travel to the right side of the heart and from the heart to the lungs. Air trapped in vessels providing blood to the lungs can inhibit pulmonary circulation and cause chest pain and rapid breathing. In some patients, the air may pass to the left side of the heart and on to the brain or the coronary arteries, which can lead to more serious complications. The effect of an air embolism is directly related to the size of the embolus and the rate of entry of the air into the blood vessel. 50 ml of air cause hypotension and dysrhythmias, while 300 ml can cause death if introduced rapidly, generally due to circulatory obstruction and cardiovascular collapse.
Air can become introduced in the blood vessels during surgery or another medical procedure, such as from a syringe. Air may be introduced in the form of bubbles trapped in a fluid introduced into the blood vessel (e.g., a blood transfusion, an intravenous (IV) fluid line supplying a fluid such as a saline solution or medicine). Small air bubbles may be present in the fluid as supplied. Additional air bubbles may be formed, for example, when priming the IV line if a roller clamp is released too quickly when priming the line.
A pump may be used to control the rate at which the fluids are introduced. Such pumps may include a system to detect when air is in the IV line. If an air bubble reaches the pump, an alarm may sound to alert the nursing staff or other caregiver and the pump turns off. The caregiver then must go to the patient, attempt to remove the air bubbles from the IV line. Every health care facility may have a specific protocol for this procedure, but it may involve low-tech and/or time consuming solutions such as “flicking” the IV bag and/or IV line to try and release the bubbles and get them to collect at the top of the bag, away from outlet.
Hundreds of millions of dollars and many hours of labor are spent by the nursing staff or other caregivers to initially prime the IV line, reset the pump alarm when it goes off, and purge air from the IV line. Additionally, the alarm built into the pump is a disturbance to the patient, as it is likely to wake the patient every time it goes off.